DE3601272C2 - - Google Patents

Description

The invention relates to an adhesive.

From DE-OS 17 19 169 an adhesive is known which contains a polyisocyanate and a copolymer which from one or more alkyl acrylates in which the Alkyl groups are linear carbon chains of about 4 to 12 Have carbon atoms, and one or more other polymerizable ethylenic monomers, from which at least one is a functional group with a having active hydrogen atom exists. Especially suitable polyisocyanates are those which by partial reaction with a polyol or another Compound with two or more active hydrogen atoms are modified. The glue is used to join Vinyl halide polymers.

Vulcanized rubbers of the polyolefin type, such as ethylene Propylene diene terpolymer rubber (EPDM) and ethylene Propylene copolymer rubber (EPM), and synthetic resins polyolefin type such as polypropylene (PP) and polyethylene (PE), have excellent weather resistance, Aging and ozone resistance compared to  Natural rubber (NR), synthetic rubber, such as styrene Butadiene copolymer rubber (SBR), polybutadiene rubber (BR), isobutylene-isoprene copolymer rubber (IIR), Polychloroprene rubber (CR), acrylonitrile butadiene Copolymer rubber (NBR) and polyisoprene rubber (IR), and synthetic resins such as ABS resin, polystyrene resin (PS), Acrylonitrile-styrene copolymer resin (AS) and ethylene-vinyl acetate Copolymer resin (EVA), and have working temperatures in wide ranges from -50 ° C to 150 ° C. As rubbers and have synthetic resins with excellent properties they found use in numerous applications.

Vulcanized rubbers of the polyolefin type, such as EPDM and EPM, and polyolefin type resins such as PP and PE no polar group in the main chains of their molecules. Therefore, adhesive layers applied thereto tend to be coated to relieve. Strong adhesion is only extreme Difficulties between such rubbers or resins of the Polyolefintyps achieved between rubbers of the Polyolefin type on the one hand, and resins of the polyolefin type on the other hand, between rubbers or resins of the Polyolefin type on the one hand and other substances, such as Metals and plastics, on the other hand.

To overcome these disadvantages have been to date tried to apply various measures. None of the However, the measures applied so far proved to be satisfactory.

With a view to solving the problems described above The inventor has a study looking for one Adhesive for vulcanized rubbers of the polyolefin type and continued for many years for polyolefin type resins and now found an adhesive that has the ability  has to adhere to such substrates with sufficient strength.

By the invention, the problem to be solved, a Adhesive that is capable of producing a strong and to achieve lasting connection when on one Vulcanized rubber of the polyolefin type or a Synthetic resin is applied to this with a other vulcanized rubber of the polyolefin type or a synthetic resin or with a metallic one Substance or another synthetic resin connect.

This object is achieved according to the invention by a Adhesive containing (a) a copolymer of (a1) Acrylic acid, a derivative thereof having not more than 18 Carbon atoms, methacrylic acid or a derivative thereof with not more than 18 carbon atoms with (a2) one active hydrogen-containing compound and (b) a Urethane prepolymer with terminal NCO groups, available by reaction of a mixture of polyether or Polyesterpolylol and triethanolamine in a molar Mixing ratio of 1 / 0.05 to 2 with polyisocyanate.

The present invention can be applied to a molded article Attachment structure can be applied, which the Molding stuck to another object for a long time, for example, on a car, stops. The molding will be included by means of an adhesive tape on which the adhesive according to the invention is located on an object attached.

Further applications of the invention will become apparent from the understanding of one described below  preferred embodiment and the claim. At the Working with the invention will provide the skilled person many advantages do not recognize in the present description are mentioned.

The invention will be described below with reference to FIGS Drawings described. In detail shows

Fig. 1 shows a cross section of a structure for mounting a molding, using the adhesive according to the invention,

Fig. 2 is a cross-sectional view of a structure for attaching a blank, as an example of a practical application of the invention.

In the following the connections are described in detail, from which the adhesive according to the invention consists, the on the surface of different substrates, made of one Resin of polyolefin type or of vulcanized rubber of the polyolefin type.

Acrylic acid derivatives having not more than 18 carbon atoms include aliphatic alkyl acrylates, such as methyl acrylate, Ethyl acrylate, n-butyl acrylate, isobutyl acrylate, 2-ethylhexyl acrylate, Isodecyl acrylate, lauryl acrylate, mixed C₁₂-C₁₃ alkyl acrylates, stearyl acrylate and mixed C₁₀- C₁₈ alkyl acrylates, for example. It can also use acrylic acid itself become.  

Methacrylic acid derivatives with not more than 18 Carbon atoms include aliphatic alkyl methacrylates, such as methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, Isobutyl methacrylate, 2-ethylhexyl methacrylate, Isodecyl methacrylate, lauryl methacrylate, mixed C₁₂-C₁₃- Alkyl methacrylates, stearyl methacrylate and mixed C₁₀- C₁₈-alkyl methacrylates, for example. Methacrylic acid itself can also be used.

As specific examples of the active hydrogen-containing Compound may be 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, Maleic acid, maleic anhydride, fumaric acid, Citric acid, citric anhydride, itaconic acid and Itakonsäureanhydrid be called, as well as acrylic acid and Methacrylic acid.

An active hydrogen-containing acrylic adhesive can by copolymerization of a methacrylic or acrylic acid derivative with not more than 18 carbon atoms with one active hydrogen-containing compound by the conventional methods are obtained. In this case can a mixture of a methacrylic acid derivative and a Acrylic acid derivative containing an active hydrogen Compound be copolymerized.

The term "urethane prepolymer" as used in this invention is supposed to mean a product that is involved in the reaction between a mixture of a polyol with a triethanolamine and a polyisocyanate, and which is available on the Contains an NCO group.

As the polyol is a polyether polyol or a polyester polyol,  which is at least one bifunctional group contains, used.

Examples of the polyether polyols include diols such as polyethylene glycol, Polypropylene glycol, polytetramethylene glycol, Poly (propylene oxide-ethylene oxide) glycol, propylene oxide Glycerol reaction product and propylene oxide Trimethylolpropane reaction product.

Examples of the polyester polyol are adipic acid esters, such as Polyethylene adipate, polybutylene adipate and polyethylene butylene adipate.

Concrete examples of the polyisocyanate include toluene diisocyanate, 4,4'-diphenylmethane diisocyanate, hydrogenated 4,4'- Diphenylmethane diisocyanate, 1,5-naphthalene diisocyanate, Xylene diisocyanate, hydrogenated xylene diisocyanate, isophorone diisocyanate and 1,6-hexamethylene diisocyanate.

The above urethane prepolymer can be prepared by Dissolving said polyol, isocyanate and triethanolamine in a solvent such as trichlorethylene and by Heating the resulting solution to react in one Atmosphere of dry nitrogen gas at 80 ° C during three Hours, as usually done in practice becomes. In this reaction, the urethane prepolymer can be reacted with an NCO Group will be preserved in the end.

The mixing ratio, the equivalent weight of the polyol to that of the polyisocyanate, OH / NCO, is preferably in the Range of 1 / 1.5~7.

When the amount of NCO is less than 1.5 equivalent weights is, the adhesive strength is intolerably low. If  it exceeds 7 equivalent weights, brings the excess NCO no increase in adhesive strength.

The mixing ratio of the polyol to the triethanolamine is such that the amount of triethanolamine in the area from 0.05 to 2 moles per mole of polyol.

When mixing the active hydrogen-containing acrylic adhesive, which is the copolymer of the cited Methacrylic acid derivative and / or acrylic acid derivative and the active hydrogen-containing compound is, with the urethane prepolymer in a solvent, is the mixing ratio of these two components preferably such that the amount of urethane prepolymer as a solid falls in the range of 0.007 to 500 parts by weight, preferably 0.007 to 100 parts by weight, per 100 parts by weight the amount of the active hydrogen-containing acrylic adhesive as a solid.

When the amount of the urethane prepolymer as a solid is less than 0.007 Parts by weight, the adhesive strength is intolerable low. If the amount exceeds 500 parts by weight, the excess does not increase the adhesion more, and the time required for curing is extended.

Examples of the solvent effective during the Mixing the two components mentioned above will include, aromatic hydrocarbons, such as benzene, Toluene and xylene, ketones such as methyl ethyl ketone, methyl isopropyl ketone and methyl isobutyl ketone, acetic acid ester, such as  Methyl acetate, ethyl acetate, isopropyl acetate and Isobutyl acetate, and saturated hydrocarbons, such as n- Hexane and cyclohexane, a.

The application of the adhesive with the above Composition which differs on the surface Substrates of a polyolefin type resin or of vulcanized rubber of the polyolefin type is used can be through Use of one of the known application techniques, such as Dipping, spraying and brushing, without any special apparatus, executed.

Optionally, the substrate may be corona discharge or Subjected to plasma treatment to activate its surface before it is coated with the adhesive.

The corona discharge treatment can be among the following Conditions are executed: z. B. 1 kW electrical Power, a knife-type electrode, 300 mm electrode length, and 1 mm distance between the electrode and the substrate.

In the following examples were the adhesives of the invention for adhesive strength tested.

An EPDM composition, shown in Table 1, was vulcanized at 160 ° C for 30 minutes to give one Test piece of 2 mm thickness. (In the following mean always all parts mentioned in the tables parts by weight).

EPDM 100 parts soot 67.5 Erdlöl 35 zinc oxide 5 stearic acid 1 sulfur 1.5 vulcanization accelerators 2

The surface of the test piece was below the above Subjected to conditions of corona discharge treatment.

Thereafter, an adhesive consisting of a mixture of a active hydrogen-containing acrylic adhesive and a Urethane prepolymer was prepared on the treated surface of the test piece, followed by 2 minutes Dried 100 ° C.

The two test pieces so coated with the adhesive were joined together with their adhesive sides connected, allowed to stand at room temperature for 20 days and then a shear strength test with a Dehngeschwindigkeit of 30 mm / min subject.

The composition of the urethane prepolymer contained in the adhesive is contained, the mixing ratio of the urethane prepolymer to Acrylic adhesive, and the shear strength are in Table 2 shown.  

The active hydrogen-containing acrylic adhesive, the was used, was prepared as follows.

• 1. Active hydrogen-containing acrylic adhesive A:
  A copolymer of n-butyl acrylate and maleic anhydride (acid value = 20 to 25) was diluted to a solid content of 37% with a 1: 1: 1 mixed solvent of toluene: cyclohexane: ethyl acetate (weight ratio, hereinafter applicable) (hereinafter "Acrylic adhesive A").
• 2. Active hydrogen-containing acrylic adhesive B:
  A copolymer of n-butyl acrylate and fumaric acid (acid value = 30 to 32) was diluted to a solid content of 37% with a 1: 1: 1 mixed solvent of toluene: cyclohexane: ethyl acetate (hereinafter referred to as "acrylic adhesive-B").
• 3. Active hydrogen-containing acrylic adhesive C:
  A copolymer of n-butyl acrylate and 2-hydroxypropyl methacrylate (OH number = 54 to 58) was diluted with the above-mentioned solvent to a solid content of 37% (hereinafter referred to as "acrylic adhesive-C").
• 4. Active hydrogen-containing acrylic adhesive D:
  A copolymer of n-butyl acrylate and 2-hydroxyethyl methacrylate (OH number = 36 to 30) was diluted with the above-mentioned solvent to a solid content of 37% (hereinafter referred to as "acrylic adhesive-D").

In Examples 1-15, the acrylic adhesive A was used used.

The urethane prepolymers used in these examples were varies by changing the mixing ratio of Polyol and triethanolamine and the type of isocyanate to the for the sake of exact comparison.

The urethane prepolymer of Example 1 was z. B. made by Combine 1 mole of polypropylene glycol (molecular weight = 3000) with 0.7 mol triethanolamine in trichlorethylene, by Adding 4,4'-diphenylmethane diisocyanate to the resulting solution in such an amount that an OH / NCO Ratio of 1/4 obtained by heating for three hours Mixture for reaction at 80 ° C in an atmosphere dry nitrogen gas, and adding 19 parts Toluene to 1 part of the resulting solution (solids content 83%).  

Table 2

The adhesive of Example 1 was prepared by mixing 1 Part of this urethane prepolymer with 100 parts of said acrylic adhesive A received.

Comparative experiment 1 in Table 2 represents a case in only the acrylic adhesive-A was used, and the Shear strength was essentially 0.

The adhesives in Comparative Examples 2 and 3 needed too much time to cure to make a measurement of To allow shear strength.

In the results of the shear strength test was found that the adhesives in Examples 1-15 have an extremely high adhesive strength.  

In the following, embodiments of the molded article Mounting structure for use of the adhesive the Invention of automobiles described with reference to the Drawings.

In general, a car body moldings Vinyl chloride resin attached to it for two reasons  are: for the protection and decoration of the car body.

As shown in Fig. 2, a resin molding 2 is fixed to a car body 1 by means of a double-sided adhesive tape 4 .

This double-sided adhesive tape 4 is prepared by applying an acrylic type adhesive 6 such as butyl acrylate, butyl methacrylate or 2-ethylhexyl acrylate on both sides of a substrate 5 made of a thin foam layer of acrylic rubber, polyethylene or chloroprene rubber, a nonwoven fabric, a film or paper consists. Since the acrylic type adhesive 6 used on the tape does not have sufficient adhesive strength, there is the possibility that the molded article 2 will peel off from the car body 1 after a long period of use.

Therefore, the inventor has means for using the Adhesive of the invention in said molding Fastening construction invented. To the effect of this Being able to estimate construction became the following test carried out.

test method

The named adhesive, which consists of an active hydrogen formed acrylic adhesive and a urethane prepolymer formed was applied to the surface of a foam substrate, by foaming polyethylene fivefold of its original volume, applied.

Thereafter, the substrate quickly became one acrylic coated metal plate fixed, 24 hours  let stand, and with a strain rate of 30 mm / min for shear strength.

The compositions of the adhesives used in the examples 1-15, the comparative experiments 1-3, as well as their shear strength values are shown in Table 5. In Table 5, Comparative Experiment 1 represents a case in which the acrylic adhesive alone was used. The Shear strength of this adhesive was essentially 0.

The adhesives of Comparative Experiments 2 and 3 required a lot of time to cure, to measure the shear strength too can.

Comparative experiment 4 represents a case where a Commercially available double-sided adhesive tape was used.  

Table 4

From the results of the shear strength test, which in Table 4, it is apparent that the adhesives Examples 1-16 have a very high adhesive strength and their effect in said molding attachment construction clearly reveal.

Fig. 1 shows a construction for fixing a molded article 2 , which is obtained by applying the adhesives 3, 8 to a substrate 5 of a double-sided adhesive tape 14 .

In this construction, the adhesive 3 on the side of the substrate 5 facing the molding 2 can be replaced by other adhesives such as chloroprene rubber or urethane type resin.

The molding attachment structure using the adhesives 3, 8 of the invention can be used not only for fixing the molding 2 to the automobile body 1 , but also for attaching a synthetic resin material to a metal or other material by means of a double-sided adhesive tape 4 .

Claims (1)

Adhesive containing

• (a) a copolymer of
  • (a1) acrylic acid, a derivative thereof having not more than 18 carbon atoms, methacrylic acid or a derivative thereof containing not more than 18 carbon atoms
  • (a2) an active hydrogen-containing compound and
• (b) an NCO-terminated urethane prepolymer obtainable by reacting a mixture of polyether or polyester polyol and triethanolamine in a molar mixing ratio of 1 / 0.05 to 2 with polyisocyanate.